1. Field of the Invention
This invention relates to blends of fluorinated and non-fluorinated thermosetting monomers and resultant cured products used to produce resins with modified surfaces.
2. Description of the Prior Art The fluorinated diol of structure ##STR1## where R.sub.f =H or C.sub.n F.sub.2n+1 for n=1-18 has proven to be a highly useful intermediate for the production of various thermosetting resins. For example, when reacted with an excess of epichlorohydrin it produces a diglycidyl ether which may be crosslinked with polyfunctional amines to produce a fluorinated epoxy resin (see U.S. Pat. No. 3,879,430). When reacted with a stoichiometric quantity of epichlorohydrin and another diol it produces a fluorinated polyol which may be crosslinked with polyfunctional isocyanates to produce a fluorourethane (see U.S. Pat. No. 3,720,639, U.S. Pat. No. 3,852,222, U.S. Pat. No. 4,157,358, and commonly assigned, co-pending U.S. patent application Ser. No. 277,089, filed Nov. 28, 1988). When reacted with the appropriate acid chloride, it produces a diacrylate or dimethacrylate which may be polymerized to produce the corresponding fluorinated acrylate or methacrylate resin (see U.S. Pat. No. 4,356,296). When the diglycidyl ether of the fluorinated diol is reacted with acrylic acid or methacrylic acid, it produces yet a different diacrylate or dimethacrylate which may be polymerized to fluorinated resins (see commonly assigned co-pending U.S. patent application Ser. No. 263,152, filed Oct. 26, 1988 now U.S. Pat. No. 4,914,171). In other words, the fluorinated diol above may be used as an intermediate to produce a variety of difunctional fluorinated monomers which may be polymerized to produce a variety of fluorinated resins.
The properties of these fluorinated resins are similar to both those of the corresponding non-fluorinated resin and those of a fluoropolymer. In general the thermal and chemical properties of the fluorinated resin are similar to the non-fluorinated material and seem to depend primarily on the chemical linkages produced during polymer formation. On the other hand the fluorinated resins possess a number of properties similar to common fluoropolymers--low moisture absorption, low moisture permeation, low surface energies, low dielectric constants, low index of retraction, low coefficients of friction, and many others--when compared to their non-fluorinated analogues.
The usefulness of the fluorinated resins discussed above depends primarily on their more unique fluoropolymer properties. Application of these resins as oil and water repellents, as biological anti-fouling materials, as marine coatings, as cladding for optical fibers, as low dielectric materials for electronic application, as adhesives, as moisture barrier coatings, as wear reducing agents and many others are possible. In some cases the application of the fluorinated resins depends upon their bulk properties (such as required for electronic and optical applications) and in other cases their application depends on surface properties (such as oil and water repellency or antifouling applications).
For many practical applications the use of the fluorinated resins is restricted by either or both of two factors. First, in order to achieve high levels of fluoropolymer like properties the difunctional monomers used to make the resins must contain fluoroalkyl groups, R.sub.f, of significant length (e.g. n=6 to 10). The molecular volume occupied by these groups reduces the cross-link density of the fluorinated resins as compared with many corresponding non-fluorinated resins. As a result, many of the physical properties of the fluorinated materials, such as tensile strength, hardness, glass transition temperature, etc. are reduced when compared with non-fluorinated counterparts. Secondly, the fluorinated resins tend to be quite expensive. The preparation of the basic fluorinated diol intermediate discussed above requires the use of both hexafluoroacetone and perfluorinated alkyl iodide (C.sub.n F.sub.2n+1 I) both of which are costly reagents. Many processing steps and material manipulations are required to introduce the perfluoroalkyl group to the diol, and each of these contribute to yield loss in the overall process (see, e.g. U.S. Pat. No. 3,879,430).
For applications of the fluorinated resins which depend upon their bulk properties, it is difficult or impossible to overcome the deficiencies of reduced cross-link density or cost. For applications which depend upon the surface properties of the resins, however, this is not the case. It would be desirable to provide compositions which are characterized as having fluoro-resin surface properties yet provide bulk properties of non-fluorinated resins. It would also be desirable to provide compositions which are characterized as having fluoro-resin surface properties yet which may be produced at greatly reduced costs.